Search results for "TERT"
showing 10 items of 1210 documents
Proteolytic cleavage of soybean Bowman-Birk inhibitor monitored by means of high-performance capillary electrophoresis. Implications for the mechanis…
1996
The hydrolysis of the soybean Bowman-Birk inhibitor in the presence of catalytic amounts of bovine trypsin and the formation of the non-covalent enzyme-inhibitor complex with an equimolar amount of enzyme are monitored by means of high-performance capillary electrophoresis (HPCE). The inhibitor is cleaved in the trypsin-reactive and more slowly in the chymotrypsin-reactive subdomain. HPCE proves itself as the only reliable analytical tool to monitor these reactions in clear contrast to classical electrophoretic, chromatographic and enzymatic methods. The most efficient separation of the intact and the two active site cleaved forms of the inhibitor was achieved in borate buffer at pH 10.0. T…
In-situ synthesis of thiophene-based multifunctional polymeric networks with tunable conductivity and high photolithographic performance
2017
Abstract Design of novel multifunctional polymeric materials combining electrically conducting properties with patterning capability is a significant challenge in materials science. Herein, we report on the synthesis of multifunctional interpenetrating polymer networks (IPN) by the in-situ oxidative polymerization of thiophene-based monomers with Cu(ClO 4 ) 2 inside a novolac-based photoresist. The resulting IPNs show conductivities up to 20 S/cm depending on the monomer properties. Among them, 3,3‴-Dihexyl-2,2’:5′,2’’:5″,2‴-quaterthiophene (DH4T) is chosen because it has the largest conjugation length and excellent solubility in organic solvents. Moreover, it renders a low percolation thre…
Influence of the hydrophilic face on the folding ability and stability of α-helix bundles: relevance to the peptide catalytic activity
2000
Although not the sole feature responsible, the packing of amino acid side chains in the interior of proteins is known to contribute to protein conformational specificity. While a number of amphipathic peptide sequences with optimized hydrophobic domains has been designed to fold into a desired aggregation state, the contribution of the amino acids located on the hydrophilic side of such peptides to the final packing has not been investigated thoroughly. A set of self-aggregating 18-mer peptides designed previously to adopt a high level of alpha-helical conformation in benign buffer is used here to evaluate the effect of the nature of the amino acids located on the hydrophilic face on the pa…
Isotopes Trace Biogeochemistry and Sources of Cu and Zn in an intertidal soil
2013
River floodplain soils are sinks and potential sources for toxic trace metals like Cu and Zn. We hypothesize that stable Cu and Zn isotope ratios reflect both the mobilization and the sources of metals. We determined the soil properties, the concentrations and partitioning of Cu and Zn, and variations in δ65Cu and δ66Zn values in a core obtained from an Aquic Udifluvent developed on a freshwater intertidal mudflat of the River Elbe, Germany. The core was sampled at 2 cm intervals to a depth of 34 cm, which corresponds to approximately 9 yr of sedimentation. Elevated concentrations of Cu (up to 320 μg g−1) and Zn (up to 2080 μg g−1) indicated anthropogenic pollution. At the time of sampling …
Sulfated and Non-Sulfated Glycopeptide Recognition Domains of P-Selectin Glycoprotein Ligand 1 and their Binding to P- and E-Selectin
2009
Total synthesis through block glycosylation and selective chemical O-sulfation of tyrosine residues yielded the glycopeptide recognition domain A (X=SO(3) (-)) of the P-selectin glycoprotein ligand 1, in which the terminal sialic acid of the complex hexasaccharide side chain was replaced by (S)-cyclohexyl lactic acid. In binding assays the O-sulfated structure A showed high affinity towards P-selectin, the non-sulfated towards E-selectin.
Nucleophilic substitutions in the isoindole series as a valuable tool to synthesize derivatives with antitumor activity
2011
Abstract A novel synthetic approach to the synthesis of 3-substituted isoindoles through nucleophilic substitution of 3-halo derivatives by charged carbon, and neutral nitrogen, oxygen, and sulfur nucleophiles, assisted by a 1-acyl group, is reported. Aryl-thio-isoindoles, obtained through a direct nucleophilic substitution with sulfur nucleophiles, showed cytotoxic activity, with GI50 values from micromolar to sub-micromolar concentrations, against the total number of cell lines investigated.
First reactions of dialkoxycarbenium tetrafluoroborates with pyrroles, 5H-dibenz[b,f]azepines, and electron-rich arenes
2009
Pyrrole (2a) and 2,5-dimethylpyrrole (2b) react with the dialkoxycarbenium tetrafluoroborates 1a-1c under kinetic control to yield the corresponding acylpyrrole derivatives. 5H-Dibenz[b,f]azepine (9a) and the 10,11-dihydro derivative 9b react only with the most electrophilic of the series of electrophiles tested, namely, diethoxycarbenium tetrafluoroborate (1a), to furnish the corresponding formyl derivatives. Similarly, in arene chemistry, the highly electron-rich N,N-dimethylaniline (13a) and 1,3,5-trimethoxybenzene (13b) are formylated by reaction with 1a.
Crystal structure of the bifunctional soybean Bowman-Birk inhibitor at 0.28-nm resolution. Structural peculiarities in a folded protein conformation.
1996
The Bowman-Birk inhibitor from soybean is a small protein that contains a binary arrangement of trypsin-reactive and chymotrypsin-reactive subdomains. In this report, the crystal structure of this anticarcinogenic protein has been determined to 0.28-nm resolution by molecular replacement from crystals grown at neutral pH. The crystal structure differs from a previously determined NMR structure [Werner, M. H. & Wemmer, D. E. (1992) Biochemistry 31, 999-1010] in the relative orientation of the two enzyme-insertion loops, in some details of the main chain trace, in the presence of favourable contacts in the trypsin-insertion loop, and in the orientation of several amino acid side chains. The p…
Dienediolates of unsaturated carboxylic acids in synthesis. Aldehydes and ketones from alkyl halides, by ozonolysis of β,γ-unsaturated α-alkyl carbox…
1997
Abstract A convenient two-step procedure for a two carbon homologative conversion of alkyl halides into aldehydes and methyl ketones by α-alkylation of unsaturated carboxylic acids, followed by ozonolysis is developed and applied to the synthesis of ω-chloro aldehydes. Triethylamine is superior to dimethyl sulfide or triphenylphosphine for cleavage of the ozonides, except when aldol condensation side reactions require use of protic solvents and iodide salts. Cleavage of the ozonides by triethylamine is shown to occur mainly through a reductive process.
Oxidation-responsive polyether block copolymers lead to non-ionic polymer surfactants with multiple amine N-oxides
2019
Block copolymers consisting of a nonpolar poly(propylene oxide) block and a poly(glycidyl amine) block were prepared by anionic ring-opening polymerization (AROP). The tertiary amine groups of the block copolymers were quantitively transformed into the corresponding zwitterionic amine N-oxides, as confirmed by 1H NMR and 15N NMR spectroscopy. This leads to strongly amphiphilic polyether block copolymers with multiple N-oxides. Full oxidation of the amine groups was also possible in situ in an emulsion, demonstrating the oxidation-responsive character of this new class of non-ionic polymeric surfactants.